#include <iostream>

using namespace std;

int main(void)
{
	double a, b, c;

	cin >> a;
	cin >> b;
	cin >> c;

	if (a + b <= c)
	{
		cout << "NO";
	}
	else if(b + c <= a)
	{
		cout << "NO";
	}
	else if(c + a <= b)
	{
		cout << "NO";
	}
	else
		cout << "YES";
	cout << endl;

	return 0;
}
